From: Andiry Xu <andiry.xu@xxxxxxx>
xHCI 1.0 spec says the TT Think Time field shall be set to zero if the device
is not a High-speed hub.
Signed-off-by: Andiry Xu <andiry.xu@xxxxxxx>
Signed-off-by: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx>
---
drivers/usb/host/xhci.c | 7 ++++++-
1 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 6864759..3abf332 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -2699,11 +2699,16 @@ int xhci_update_hub_device(struct usb_hcd *hcd, struct usb_device *hdev,
/* Set TT think time - convert from ns to FS bit times.
* 0 = 8 FS bit times, 1 = 16 FS bit times,
* 2 = 24 FS bit times, 3 = 32 FS bit times.
+ *
+ * xHCI 1.0: this field shall be 0 if the device is not a
+ * High-spped hub.
*/
think_time = tt->think_time;
if (think_time != 0)
think_time = (think_time / 666) - 1;
- slot_ctx->tt_info |= cpu_to_le32(TT_THINK_TIME(think_time));
+ if (xhci->hci_version < 0x100 || hdev->speed == USB_SPEED_HIGH)
+ slot_ctx->tt_info |=
+ cpu_to_le32(TT_THINK_TIME(think_time));
} else {
xhci_dbg(xhci, "xHCI version %x doesn't need hub "
"TT think time or number of ports\n",
--
1.7.4.2
--
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